


Comparing your past to my future

by MirandaTam



Category: Big Hero 6 (2014)
Genre: Do-Over, Everybody Lives, Fix-It, Gen, Though there might be some trauma and lots of property damage, Time Travel
Language: English
Status: In-Progress
Published: 2016-02-10
Updated: 2016-02-10
Packaged: 2018-05-19 11:21:17
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,175
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5965447
Author URL: https://archiveofourown.org/users/MirandaTam/pseuds/MirandaTam
Summary: <blockquote class="userstuff">
              <p>Callaghan builds a time-travel device; the six get there just in time for it to go off in their faces.</p><p>GoGo is annoyed, Wasabi is relieved, Tadashi is very confused.</p><p>But more importantly, Callaghan is vengeful.</p><p>Hiro is missing.</p>
            </blockquote>





	Comparing your past to my future

Callaghan escapes jail, of course.

That’s honestly not much of a problem (He’s not as actively threatening towards the city as some of the other villains the six face; only towards KreiTech, and most of the time they notice large amounts of technological resources going mysteriously missing in time to track him down).

At least, it’s not a problem until he builds a freaking _time travel device._

“Seriously, what,” Hiro says, right before it goes off in their faces. “Time travel. Is this science fiction, or something!? This makes _no–_ ”

 

 

“Callaghan’s still inside!” a woman gasps, and everything pauses for half a second.

Hiro stares up at the burning building, and then over at Tadashi. _Okay, then_ , Hiro thinks. _Time travel. I can work with this._

Tadashi’s staring up at the building. “I have to go. Callaghan–”

“No!” Hiro shrieks. “Tadashi–”

Tadashi’s shaking is head, and turning away, and Hiro has to stop him, has to _save_ him. He dashes forwards and tackles Tadashi.

“Hiro! Let me up!” Tadashi orders him.

“No! If you go in there–”

Hiro’s cut off by the building exploding.

“Callaghan’s fine,” Hiro tells him. “I can’t explain. There was a… a thing–”

“What are you talking about?” Tadashi shakes his head. “Let me up. We need to…” he looks over at the burning building. “To…”

Hiro rolls off of Tadashi and takes a few deep breaths, the smoke making his eyes sting. There’s a faint clicking sound coming from the building, like the sound of lots of microbots working together.

Wait.

“Oh, _shit_ ,” Hiro breathes, because Callaghan is not wasting any time. He scrambles up and away from Tadashi, he needs to get away from his brother, make Tadashi less of a target–

“Hiro Hamada,” Callaghan growls, the microbots swarming over his face in the rough shape of a Kabuki mask, “You will build me the portal, rescue my daughter, and help me have my revenge.”

“ _What_ ,” Tadashi says.

“Uh,” Hiro squeaks, and clears his throat. “Yes to the first two? Not big on revenge over here.”

Callaghan clenches his hands, and microbots swarm over to where Hiro’s standing.

“Hiro!” Tadashi yells, scrambling up and running towards him. “Run!”

A swarm of microbots whips towards Tadashi, knocking him away.

“Tadashi!” Hiro screams, but he can only take a few steps towards him before the microbots swarm around him, carrying him up and away.

 

 

Tadashi just feels… numb.

Someone had set the building on fire, stolen Hiro’s microbots, and _kidnapped Hiro_ , and the police expected him to just… go home.

Just _go home,_ and leave his _little brother_ in the hands of some _kabuki maniac_.

He needs to do something.

Tadashi stands up and starts pacing the room. There were Hiro’s old robots, and his newer one, the one he kept winning money with, and his computer, and his–

 _Meow_.

“Gaah!” Tadashi pinwheels, trying not to crush Mochi. He crashes backwards onto the floor. “Ow! Shit, goddammit, Mochi.”

A beep sounds from the corner.

“Baymax,” Tadashi sighs. “It’s okay, I just tripped, I am satisfied–”

“Tadashi,” Baymax says. “You are alive.”

“… Yes?” He looks Baymax over as the robot maneuvers out from behind his bed. “Why wouldn’t I be alive?”

Baymax looks at him, cocking his head to the side, probably performing a scan. “Minor abrasions on your arms and torso, as well as minor smoke inhalation, in the process of being treated. No signs of life-threatening injuries, such as burns.” He whirs and blinks. “Today’s Date: November 7, 2014. Hypothesis…” Baymax tilts his head the other direction, blinks twice, and raises a finger. “Time Travel.”

“ _What?_ ” Tadashi shakes his head. “Baymax, scan for computer viruses.”

“No viruses found,” Baymax reports.

Tadashi sighs and falls back onto Hiro’s bed. “I _don’t have time for this now_ ,” he growls.

“Where is Hiro?” Baymax asks.

“Not here,” Tadashi says.

“Where is Hiro?”

“He got kidnapped, okay?” Tadashi snaps. “This… this crazy guy stole his microbots, set a building on fire, and kidnapped him!”

Baymax pats Tadashi on his head. “You are experiencing signs of… distress,” he says. “One possible remedy includes reassurance from… friends and loved ones. Calling friends.”

“What?” Tadashi scrambles up. “No! No, Baymax, stop it!”

“Friends have been notified,” Baymax tells him.

“Ugh.” Tadashi falls forwards, onto Baymax. “I’m glad I made you so huggable. I do not understand what the _hell_ is going on here. Everything is going _insane_ , and I don’t know what to do.”

“… I believe that I can help,” Baymax says after a minute.

“How?” Tadashi grumbles.

Baymax whirs a bit. “Displaying recording,” he says, and Tadashi backs up so he can actually see what Baymax is playing, instead of pressing his face against it.

It’s… it’s Hiro. But it’s in this room, and Tadashi _knows_ that Hiro’s never activated Baymax in this room.

The first time Hiro says “Tadashi’s _gone_ ” he feels like he’s going to throw up, but he keeps watching. He watches Baymax wander off, them discovering the man in the Kabuki mask, Hiro teaching Baymax Karate.

“Pause,” Tadashi says, and covers his face and laughs for five whole minutes. “That is so… so typical of Hiro.” He shakes his head.

“Has this video alleviated your distress?” Baymax asks.

Oh, right, Hiro’s _gone_.

Tadashi takes a deep breath. “Temporarily,” he says, before he can start crying. “Resume.”

Baymax resumes the video, and Tadashi watches, fascinated, as Hiro makes their friends into superheroes. He’d known his little brother was a supergenius, he’d seen his crazy fighting bots and the microbots. But this… this was something different.

Tadashi laughs himself sick again, watching the first time Baymax and Hiro go flying.

And then they go sneak onto the island, and Tadashi shuts up, because this Kabuki maniac has his little brother _right now_ , and he needs to learn how to fight him.

It’s a complete disaster, of course. Hopefully they get their act together in the future. The only non-horrible part is that they still manage to get the mask off, and reveal Krei–

What.

“Pause,” Tadashi says, but he can feel his eyes watering and his breaths getting faster, and, and, and that’s… that’s the Kabuki man, who has Hiro, who kidnapped _Hiro_ , and it’s _Callaghan_ and Tadashi can’t breathe.

“You appear to be having a panic attack,” Baymax says, and begins playing soothing music. “Please attempt to breathe slowly, rather than deeply. Would you like me to count?”

Tadashi shakes his head, because he can’t talk but Baymax talking won’t help, because _Callaghan_ is a _supervillain_ and _kidnapped Hiro_ and–

“Tadashi? Tadashi!” and Baymax isn’t the only one hugging him, there’s Honey Lemon and Fred and Wasabi and GoGo, all piled on top of him and Baymax.

Tadashi takes a ragged breath in and lets himself cry.

“It’s going to be okay,” GoGo whispers into his ear. “We’re going to save him. It’s going to be okay.”

“There, there,” Baymax says, and Tadashi lets out a wet laugh.

“Okay,” he says, “Okay. I’m… I’m good. You can all get off now.”

“But Baymax is _warm_ ,” Fred mumbles, but he climbs off anyways.

“So,” Wasabi says. “Do we have a plan? Does Tadashi know what’s going on? What _is_ going on? Seriously, what the hell is going on?”

“Baymax had a recording,” Tadashi says, forcefully ignoring the way they keep looking at him out of the corners of their eyes. “Of what happened after… after I apparently, uh, anyways. I watched up to… up to when you guys first got his mask off.”

“Oh,” Honey Lemon says quietly. “You should… probably watch the next bits, maybe while we try to figure out what happened to… get us back here.”

“Time Travel,” Baymax suggests again.

“Well, the present theories don’t account for–” Wasabi starts.

“If you assume a base hypothesis of retroactive–” Honey Lemon begins.

“ _No_ theoretical phyiscs in _my_ bedroom,” Tadashi says. “Come on, guys, you know the rules.”

“C’mon, guys,” GoGo says, popping her gum. “Let’s go discuss the forbidden field of Sci-Fi somewhere else and let Asimov here finish catching up.”

“All right,” Honey Lemon says. “Baymax, call us if he gets upset again, okay?”

“I’m not a kid,” Tadashi grumbles, but doesn’t protest.

 

 

Tadashi still feels shellshocked when he gets down to the garage.

“Tadashi, bro!” Fred exclaims. “You finished?”

“I saw up to when you… defeated Callaghan, and then the device that he built before you got brought back here,” Tadashi says. “… what have you been doing down here?”

GoGo is facedown on the couch. Wasabi is in a corner. Honey Lemon is three different colors, none of which humans are supposed to be.

“Trying to rebuild our super-suits,” Fred says. “But it hasn’t been going too well.”

“I can see that,” Tadashi says, and sighs. “Here, let me try. Baymax, can you replay the recording you had of Hiro building the suits?”

Baymax obliges.

“Okay,” he says, looking over the designs carefully. “I think I can recreate this, but probably not perfectly. GoGo, let’s do you first, it looks simplest. I’m gonna need your data on what balances are needed when you’re going that speed…”

 

 

It takes five long, hard days of barely any sleep and rewatching the recordings of Hiro until he has them practically memorized before the suits are built.

Even then, Tadashi can tell that they’re not as good as Hiro’s. The others don’t say it, but he can tell they’re thinking it.

He just shakes his head, laughing a bit. “This really isn’t my specialty,” he admits. “Hiro’s special, always has been.”

The elephant in the room is that that’s why Callaghan kidnapped him.

“He’s probably on the island,” Wasabi suggests. “That’s where all the tech he needs is, anyways.”

“It’s been a week,” Honey Lemon says. “Are we sure he hasn’t relocated elsewhere?”

Tadashi shakes his head. “It took him a few months to get the portal back in working order. Even with Hiro…” his throat gets tight, and he takes a deep breath. “Even now, he wouldn’t be able to move it without breaking it further, yet. We don’t know how long it’ll take before he’s able to turn it on, but we should act as soon as possible, right?”

“Cool,” GoGo says. “But _you_ need a suit.”

“Ooh, yeah!” Fred says. “Something all… badass and robot-y!”

“I don’t know,” Tadashi says. “You all have a lot more experience than I do.”

“No way,” Wasabi says. “We just made it up as we went along!”

“You wouldn’t be in our way at all,” Honey Lemon reassures him.

“Are you sure?” Tadashi asks innocently. “You really wouldn’t mind?”

“You already built one, didn’t you,” GoGo says, popping her gum.

Tadashi goes and gets it on.

“That is _so cool_ ,” Fred says when he sees it.

“Nice,” Wasabi says.

GoGo pops her gum appreciatively. (He knows he’s known them for too long when he can tell the different moods of GoGo’s gum.)

“Oh, that is _excellent_ ,” Honey Lemon says.

His suit is red, the same shade as Baymax’s, but with grey accents instead of purple ones. He’s got a few tricks stored in it, along with the basic strength and health modifications all the suits have.

Oh, yeah, and he’s modified his motorcycle. It can’t go as fast as GoGo, but it can go on all sorts of terrain, and it can’t fully fly but it definitely won’t fall as fast or as awkwardly as a normal motorcycle would.

“All right,” Tadashi says. “Let’s do this.”

 

 

“The plan is this,” Tadashi says. “He’ll be expecting you guys to fly in on Baymax, right? But he won’t be expecting me to show up. So Fred, Honey Lemon, and Wasabi fly in on Baymax and do your best to distract him, maybe lure him outside. GoGo and I will sneak around back and grab Hiro.”

Wasabi looks deliriously happy that the plan exists. “I don’t even care that I’m going to have to fly again,” he says. “We have an actual plan. Everything is good.”

Tadashi has some reservations about his own planning skills, but… whatever makes Wasabi happy.

The plan starts going off without a hitch. Tadashi and GoGo get into the compound without any trouble, and the other four seem to be doing fine, too.

“We may have a small problem,” Honey Lemon says over the comm units in their helmets.

“If you call him _not being here_ a _small_ problem,” Wasabi snaps.

“What?” Tadashi looks back out towards where the fighting is. “He’s not there?”

“He’s just controlling them remotely,” Honey Lemon reports.

“And they keep getting back up like nothing’s wrong,” Fred adds.

“That doesn’t make any sense,” Tadashi says, shaking his head. “How would he know how to attack without being there, without seeing the fight?”

“Maybe he’s hiding,” Wasabi suggests, his voice high-pitched and panicky. “Maybe he has cameras. Maybe he’s _actually_ using ESP now.”

“There’s not enough cover for him to be hiding somewhere,” Honey Lemon points out.

“Look for security cameras,” Tadashi orders. “Take them out. GoGo, they need some backup, I’ll be fine in here.”

GoGo nods and speeds off. A few seconds later there’s a crash and a bigh cheer from Fred. “Two cameras down, three to go!”

“Three down,” Honey Lemon calls. “Two left.”

“Four down, who wants to get the last one?” Wasabi asks.

There’s a sound almost like a rocket taking off, and Tadashi winces. “What was _that?_ ”

“Baymax just rocket-fisted it,” Honey Lemon explains for his benefit. “Have you found Hiro – aah!”

“What?” Tadashi jerks back from the door he was looking into. “What happened?”

“The microbots are still fighting!” Fred yells. “Maybe he _does_ have ESP!”

“This _doesn’t make any sense_ ,” Tadashi insists. “Hiro didn’t program the microbots with sensory feedback capabilities–” _Oh, shit._

“Tadashi? What happened?” Wasabi asks after a minute of silence.

“You need to get out of there,” Tadashi says. “Get on Baymax, fly away. Go!”

“What the hell is going on?” GoGo asks.

“He got Hiro to upgrade the microbots, that’s what!” Tadashi snaps.

“Oh _shit,_ ” Fred says.

“Get out of there,” Tadashi says again. “I’ll find Hiro.”

“Unfortunately, Tadashi,” Callaghan says from behind him, “I’m afraid that you won’t.”

 

 

“I can’t believe this,” Tadashi says. “I cannot _fucking_ believe this.” He’s glaring at Callaghan, but he’s also trying to surreptitiously drop into a fighting position.

Callaghan shakes his head. “We don’t have to do this, Tadashi,” he says. “Take your friends and go home.”

“And leave my little brother?” Tadashi asks incredulously. “Never. Now, _where is he?_ ”

“Hiro’s fine,” Callaghan says. “I promise. He’ll even be back in a few days. Right now, what would be best for everyone – for _him_ – would be for you all to go.”

Tadashi shakes his head. “I don’t believe you. Just tell me where he is!”

Callaghan’s eyes grow cold. “This is your last warning, Tadashi. Leave, or I’ll make you.”

“How?” Tadashi challenges. “I don’t see any of the microbots around here.”

Tadashi’s not a _complete_ idiot. He’s thought this through. Callaghan will have to take some microbots away from the fight with the other five to fight Tadashi, and when he does, Tadashi has some tricks of his own up his sleeves. If Callaghan doesn’t take the microbots away from the other fight, Tadashi can walk right past him. It’s flawless.

“You must think I’m some kind of idiot,” Callaghan says. “First, to not notice the two different groups landing here, and second, to meet you head-on. I know how crafty you Hamada can get. What do you have stored in that suit of yours? Explosives? Electromagnets? Charges, to short out the microbots? No,” he continues, shaking his head and laughing a bit, “It doesn’t matter. What I’m telling you is this: Hiro is perfectly fine right now.” Callaghan pauses, and Tadashi gets a sinking feeling in his stomach when he sees where this is going. “It would be easy – so easy – to change that. It would really be a shame.” He sighs, and Tadashi has never wanted to punch someone in the face that much.

“Y-you wouldn’t,” Tadashi says, but he knows that Callaghan can hear the uncertainty in his voice.

“Are you sure you want to test me?” Callaghan asks in that ice-cold voice, and turns to walk away.

“Don’t you dare–” Tadashi begins, and lunges forwards to grab Callaghan, but a wave of microbots surges up and bats him aside and he slams into a wall.

“Such a shame,” Callaghan repeats, shaking his head, and walks away.

Tadashi stays down. He can’t – can’t _do_ anything, because Hiro – _his baby brother Hiro_ – is – is–

 

That’s where GoGo finds him an hour later, curled up in a corner and crying, shaking, head between his knees.

“Tadashi, hey, listen to me,” she says. “We need to get out of here, okay?”

Tadashi doesn’t reply.

“Okay,” she says, and kneels down next to him. “Dude. Listen. Things are awful. But we can get through this, okay? We’ve done it before, we’ll do it again.”

“Not _us_ ,” Tadashi manages to say. “You had Hiro, not me.”

“So?” GoGo says, and smacks him upside the head. “We’re a _team_. You’re part of it. Don’t wuss out because of some weirdo inferiority complex.”

Tadashi just sort of… shrugs, because he doesn’t care that Hiro’s better at robotics than him – he cares that _he’s_ not good enough to save Hiro. To do _anything_. To–

“Ugh. Screw this,” GoGo mutters, and picks him up. “Brace yourself,” she warns, and then zooms off, carrying Tadashi away to where the rest of the team – Hiro’s team – are waiting.

 

 

“You are – emotionally distressed,” Baymax says, back at the house.

“When did you pick up all this stuff, anyways?” Tadashi asks.

Baymax tilts his head a bit. He blinks twice. “You are… deflecting.”

Tadashi sighs. “Talking about it isn’t going to help, okay, Baymax? Just go recharge.”

Baymax is silent, save for the tiny whirr of his computer thinking, calculating. “Hiro loves you,” he says finally. “You love Hiro. This is–”

“Not enough, apparently!” Tadashi takes a deep breath. “I just… I’m so _useless_ , sitting around here. I can’t even save my own baby brother.”

Tadashi puts his head in his hands. It’s all scrambled up in his head – on one hand Callaghan, his betrayal and his threats, on the other hand _time travel_ , and everything in between all mixed up and gut-wrenchingly awful.

Then there’s a noise from behind him – Baymax, playing a recording. And it’s his voice.

“Okay, Tadashi Hamada. And this is the first test of my robotics project.”

But when Tadashi turns around to look at Baymax it’s Hiro’s face on the screen – Hiro looking lost, and heartbroken, his eyes wide, and–

“Wait ‘till my brother sees you.” On the screen, Hiro’s crying, but he’s smiling and it’s going to break Tadashi’s heart. “You are going to help so many people, buddy.”

Tadashi brushes his fingers across Hiro’s face on the screen, and takes a deep breath.

 _Now_ , he thinks, _I’m going to help_ you.

**Author's Note:**

> Title, of course, from Immortals by Fall Out Boy from the movie Big Hero 6.
> 
> Honestly not sure if there is going to be another chapter of this - college is tough and trying to fix up my NaNoWriMo Horror is tougher. But this has been sitting in my WIP folder for over a year now, so I figured it was finally time to shove it out into the wilds and see how it held up.


End file.
